1. Field of Invention
This invention generally relates to the field of secure information communication.
2. Description of Related Art
A group of users can generally communicate securely over a public channel when they all share a common key, such as, for example a session key, which is used to encrypt messages and other communications. Because the group of users may change over time, for example, because some existing users leave the group and/or because some new users join the group, it is desirable to change the encryption communication common key periodically.
Conventional techniques and methods for secure communication have generally been provided for distributing an encryption communication common key over a reliable channel or network.
Often, changing the encryption communication common key must be performed using an unreliable, or lossy, network. However, in an unreliable network, a key distribution broadcast for a particular session might never reach a user in the group. Requiring that each such user contact the group manager to request a re-transmission of the key would contribute to the traffic on a network that might already be heavily burdened. Furthermore, when the user group size is large, such re-transmissions could potentially overwhelm the group manager. Moreover, in some high security communication environments, such as, for example, military applications, it can be important that users avoid sending all but essential messages, lest they make themselves vulnerable by revealing their location.